Vidic was lucky to escape a red card just five minutes into the match after he was the last man when bringing down Gabriel Agbonlahor in the penalty area.

James Milner scored from the resultant penalty-kick, but Michael Owen equalized before Wayne Rooney won the game for the Red Devils in the 74th minute.

And when quizzed about the incident, O’Neill told Sky Sports, “I think everybody felt that, everybody except the man who made the decision.

“I don’t think there’s any query about it and the more you see it the more it’s so puzzling. It’s a big, big point in the game.

“We were absolutely fantastic, particularly in the first half of the game. We took the game to Manchester United and we played some scintillating football.

“We’re a really great side that is improving and has the ability to do that, and I thought we had wonderful support, which was terrific as well.

“Manchester United obviously came more into the game in the second half and caused us one or two problems, but we were always dangerous in the game.

“Getting back to the major point in the game and Manchester United, without doubt, should have been playing the game with 10 men for what is 83 minutes.”

O’Neill spoke to Dowd at the final whistle, but refused to tell the press the explanation the referee gave.

He added, “That will remain between myself and the referee, who is otherwise a very fine referee, but I thought he got this one wrong and I think anybody who witnessed this on TV or during the course of the game today would probably side with me.

“The problem with it, of course, is it’s a bit sour grapes because we’ve got beaten in the game by a really fine Manchester United team, but in two, three weeks’ time it’s forgotten and the trophy goes to Manchester United.

“We end up losing. I think anybody who knows anything about the game thinks that was a major decision.”

The Villa boss says the red card could have really changed the outcome of the game.

“Eventually who knows what the outcome would be, but I would say it would be a difficult battle to play in these conditions,” continued O’Neill.

“Wembley is not in the best shape at the minute, it was very difficult conditions and playing with 10 men and a goal behind, we’re a very capable side.

“That should have been the scenario, but it wasn’t.

“We’re improving rapidly and I hope this taste of Wembley here will drive us more to come back.”